#include <stdio.h>

int my_sum(int m, int n){
	if(m>n){
		return -1;
	}

	int sum = 0;
	int i = 0;
	for(i = m; i <= n ; i++){
		sum+=i;
	}
	return sum;
}

int main(int argc, const char *argv[])
{
	int ret = my_sum(1,200);
	if(-1 == ret){
		printf("函数调用失败\n");
		return 0;
	}
	printf("ret = %d\n", ret);//5050

	return 0;
}
